Synthetic thread or fiber and process for the production thereof



SYNTHETIC THREAD R FIBER AND PROCESS FOR THE PRODUCTION THEREOF RudolfLotz, Kliugenberg (Main),

Vereinigte Glanzstolf-Fabriken feld, Germany No Drawing. Filed Apr. 24,1956, Ser. No. 580,167 -Claims priority, application Germany Aug. 8,1955 18 Claims. (Cl. 260-45.7)

Germany, assignor to A.G., Wuppertal-Elber- This invention relates to animproved synthetic thread or fiber and to a process for producing thesame, and is a continuation-in-part of my application, Serial No.572,223, filed March 19, 1956, now abandoned.

It is well known that threads or fibers of synthetic high polymers havean electrostatic charge which is detrimental in later operations on thethreads, such as weaving.

Attempts have been made to reduce the amount of the electrostatic chargeon the threads or fibers by additional processing of the threads, forexample, by treating the formed threads with solutions of low molecularweight condensation products. By this treatment the condensation productbecomes fixed on the threads and remains fixed on the threads throughsubsequent laundering operations. Other treatments employed involvechemical coupling reactions such as are involved in the substantivedyeing of threads. with reduced electrostatic charge but isdisadvantageous in that the substances applied by the treatment causeyellowing of the threads. Furthermore, machinery used in laterprocessing of the treated, threads and fibers becomes corrodeddue to thetreating solutions employed. The corrosion of the machinery,

in turn, has detrimental elfects on the threads and fibers.

- One of r the objects of the invention is to provide a synthetic threador fiber of reduced electrostatic charge and aprocess for producing thesame.

Another object of the invention is to provide a process for producing asynthetic thread or fiber of reduced electrostatic charge which processwill not cause discoloration of the'threads or fibers and which will notcause corrosion of machinery employed in later operations on the threadsIn accordance with the invention, these objects are accomplished byincorporating in the linear polymer prior to the spinning of the threador fiber a derivative of methane This type of after treatment producesthread or ethane which dissociates into free radicals having tri-'valent carbon. The derivative is added to tthe polymer just prior tospinning the thread or fiber or is added prior to polymerization to themonomer from which the linear polymer is formed.

. The monomers polymerized to form the linear polymers from which thethreads or fibers are spun are any of those customarily employed inproducing linear high polymers by polycondensation, in which some atomicdisplacement. occurs, or by true polymerization in which no atomicdisplacement occurs. Examples of such monomers' are lactams,hexamethylenediammoniumadipate, 'terephthalic acid dimethyl or diglycolesters, and acrylic acid nitrile. These monomers or other like monomersare polycondensed or polymerized in the presence of the aforementionedmethane or ethane derivatives by otherwise conventional methods.

Any methane or ethane derivative or mixtures thereof are suitable whichdissociate in solution into free radicals having trivalent carbon. Thederivatives found to be esylchloromethane, triphenylcarbinol,diphenylmonobiphen- Meter,

2,957,848 Patented Oct. '25, '1960 ylmethane, phenyl-di-biphenylmethane,diphenyl-a-naphthylmethane, hexaphenylethane, hexa-p-diphenylethane,tetraphenyl-di-biphenylethane, diphenyl-tetra-biphenylethane, andhexa-biphenylethane. V

1 The above-named derivatives or anti-static additives can best berepresented by the general formula and wherein R R R512 R and R aremonovalent aryl radicals selected fromthe group consisting ofunsubstituted and chloro-substituted phenyl, naphthyland diphenylradicals. These compounds are more fully discussed in Gilman, OrganicChemistry, vol. I, second ed., John Wiley & Sons, New York, pp. 581-601.Gilman notes that these compounds are characterized by their property ofdissociating into free radicals which are referred to as thetriarylmethyls and in which the carbon atom is trivalent, the oddelectron resonating among nine positions according to prevalent theoriesof resonance. It is this resonance which is believed to contribute tothe unique stability of the trivalent carbon atom.

The particular anti-static compound employed is added to the monomer tobe polymerized or the polymer in an amount which is relatively smallcompared to the amount of monomer or polymer employed, preferably anamount ofiabout 0.1to 5% by weight of the monomer or polymer. Theanti-static compounds are added to the monomers or polymers eitherdirectly or in solution employing an appropriate solvent for theanti-static compound such as a-chloronaphthalene or1,2,4-trichlorobenzol.

Threads or fibers produced from linear high polymers have anelectrostatic charge which is measurable by a megohm-meter, based on theprinciple that the electrical resistance of the thread or fiberincreases proportionally with increased electrostatic charge on thethread or fiber. A suitable megohm-meter, known as a Multi-Megohmisobtainable from Wissenschaftlich-Technische Werkstiitten, Wessobrunn,Upper Bavaria, Germany. It has been found that the electrostatic chargeon a thread is excessive and detrimental to later processing of thethread if the measured resistance of the thread is 5 10 ohms or more.

The invention will be further illustrated but is not limited by thefollowing examples in which the quantities are stated in parts by weightunless otherwise indicated.

Example 1 A linear high polymerwas produced by heating grams ofterephthalic acid dimethyl ester with 20 milligramsof zinc oxide and anequimolecular excess of ethylene glycol, in a nitrogen atmosphere untila clear solution was formed. To this solution was added 2 grams ofhexaphenylethane, and the mixture was further heated in the nitrogenatmosphere for three hours at normal atmospheric pressure with thetemperature of the mixture gradually increased to about '200 C.- Whenglycol separation was substantially completed, the mixture was furtherheated to 265 C. for one hour. Vacuum was then applied to remove tracesof glycol. The polycondensate obtained had a K-value of 50. Threadsproduced from the polycondensate had an electric resistance of about1x10 ohms; indicating a sufiiciently low electrostatic charge. Apolycondensate produced by the same process with'the exception that thehexaphenylethane was omitted was 3 spun into threads which were found tohave an electrical reslstance between 1 10 and 1 10 ohms, indicating anexcessively large electrostatic charge.

Example 2 100 grams of terephthalic acid diglycol ester was dissolved in350 grams of a-methylnaphthalene with heating during which 20 milligramsof boron trioxide were added.

,To the solution obtained was added 1.5 grams of tri- Example 3 Amixture containing 113 grams of a lactam having the formula 1.2 gramse-amino capronic acid, 8 milliliters distilled water and 1.2 gramsdiphenyl-mono-biphenylmethane was heated to a condensing temperature(about 235 C. bath temperature). After 7 hours of heating, a polyamidewas formed from which synthetic threads were produced. The electricresistance of the threads was found to be about 1X10 ohms, indicating asufficiently low electrostatic charge.

Example 4 400 grams of freshly distilled acrylic acid nit-rile wassuspended in 400 milliliters of water containing 0.5 gram ammoniumpersulfate, 1.0 gram ammonium sulfite and 2.0 grams of an emulsifyingagent (a polyethoxylated fatty acid formed from 6 parts ethylene oxideand 1 part stearic acid). To this suspension was added 0.1 gramtriphenylchloromethane and 0.1 gram hexaphenylethane. The mixture wasthen heated at 235 C. for 4 to 6 hours with constant agitation. Theresulting polymerizate was removed from the mixture by precipitationwith sodium chloride, filtered and washed with water. Threads producedfrom the polymerizate had an electrical resistance of 1x10 ohms,indicating a sufficiently low electrostatic charge.

Example 5 17 parts by weight of polyacrylic nitrile were dissolved in 83parts by weight of dimethyl formarnide. To this solution was added 0.50f triphenylchloromethane and the solution then spun into threads. Theresulting threads had an electrical resistance of 0.11 X ohms,indicating a sufficiently low electrostatic charge.

Example 6 17 parts by weight of polyacrylic nitrile were dissolved in 83parts by weight of dimethyl formamide. To this solution was added 1%hexaphenylethane and the resulting mixture spun into threads. Theelectrical resistance of the threads was found to be 014x10 ohms,indicating a sufliciently low electrostatic charge.

Example 7 To 100 parts by weight of a polyamide, formed fromcaprolactam, was added 1% diphenyl-a-naphthyhnethane, after which themixture was melted and spun into threads. The electrical resistance ofthe threads was found to be 10 ohms, indicating a sufiiciently lowelectrostatic charge.

4 Example 8 parts by weight of polyethylene terephthalate (K- value of50) was added to 100 parts by weight of achloronaphthalene containing0.5% of hexaphenylethane. After removing most of the a-chloronaphthaleneby distillation, the mixture was melted and spun into threads. Theelectrical resistance of the threads was found to be 4X10 ohms,indicating a sufficiently low electrostatic charge.

All of the threads or fibers produced according to the invention in theabove examples had a sufficiently reduced electrostatic charge to avoiddetrimental electrostatic effects in later processing of the threads.The anti-static methane or ethane derivatives incorporated in thepolymer threads or fibers are chemically resistant and accordingly arenot washed out of the polymer threads in subsequent launderingoperations. Furthermore, the threads or fibers produced according to theinvention are not discolored due to the special processing and becauseof their antistatic characteristics are highly desirable in the textileindustry.

The invention is hereby claimed as follows:

1. An improved synthetic fibrous material comprising a linear highmolecular weight synthetic fibrous polymer selected from the groupconsisting of polycaprolactam, polyhexamethylene adipamide andpolyethylene terephthalate to which there has been added an anti-staticcompound having the general formula R1 RQC-Y Rt wherein Y designates amember selected from the group consisting of hydrogen, chlorine, hydroxyand R4 C--R;

R0 and wherein R R R R R and R are monovalent aryl radicals selectedfrom the group consisting of unsubstituted and chloro-substitutedphenyl, naphthyl and diphenyl radicals.

2. A synthetic fiber according to claim 1 wherein said polymer ispolycaprolactam.

3. A synthetic fiber according to claim 1 wherein said polymer ispolyethylene terephthalate.

4. A synthetic fiber according to claim 1 wherein said anti-staticcompound is hexaphenylethane.

5. A synthetic fiber according to claim 1 wherein said anti-staticcompound is triphenylchloromethane.

6. A synthetic fiber according to claim 1 wherein said anti-staticcompound is diphenylmonobiphenylmethane.

7. A synthetic fiber according to claim 1 wherein said polymer containssaid anti-static compound in an amount of about 0.1% to about 5% byWeight of the polymer.

8. A synthetic fiber according to claim 1 wherein said anti-staticcompound is hexa-p-diphenylethane.

9. A synthetic fiber according to claim 1 wherein said anti-staticcompound is hexa-biphenylethane.

10. A synthetic fiber according to claim 1 wherein said polymer ispolyhexamethylene adipamide.

11. In a process for producing a synthetic fibrous material wherein amonomer is polymerized to form a linear high molecular weight polymerselected from the group consisting of polycaprolactam, polyhexamethyleneadipamide and polyethylene-terephthalate and the polymer is spun into afilamentary product, the improvement for reducing electrostatic chargeson the filamentary product which comprises: adding to said fibrousmaterial prior to spinning the filamentary product an anti-staticcompound having the general formula wherein Y designates a memberselected from the group consisting of hydrogen, chlorine, hydroxy and/R4 -C R; u and wherein R R R R R and R are monovalent aryl radicalsselected from the group consisting of un:

substituted and chloro-substituted phenyl, napthyl d ed diphenylradicals, said anti-static compound being a in an amount suflicient toavoid detrimental electrostatic charges in subsequent processing of thefilamentary product.

12. The improvement according to claim 11 wherein said anti-staticcompound is incorporated in the polymer in an amount of about 0.1% toabout 5% by weight of the polymer.

13. The improvement according to claim 11 wherein said anti-staticcompound is dissolved in a-chloronaphthalene prior to incorporation inthe polymer.

14. The improvement according to claim 11 wherein said anti-staticcompound is dissolved in 1,2,4-trichlorobenzol.

15. The improvement according to claim 11 wherein said anti-staticcompound is hexaphenylethane.

16. The improvement according to claim 11 wherein said anti-staticcompound is triphenylchloromethane.

17. The improvement according to claim 11 wherein said anti-staticcompound is diphenylmonobiphenylmethane.

18. The improvement according to claim 11 wherein the anti-staticcompound is incorporated in the polymer by addition prior topolymerization to the monomer from which the polymer is formed.

References Cited in the file of this patent UNITED STATES PATENTS2,115,896 Wiezevich May 3, 1938 2,223,171 Gaylor Nov. 26, 1940 2,445,739Rowland et a1 July 20, 1948 2,763,635 Tucker et al Sept. 18, 19562,841,569 Rugg et al. July 1, 1958 FOREIGN PATENTS 455,527 Canada Mar.29, 1949 OTHER REFERENCES Wooding et a1.: Chemical Society Journal,January- 25 March 1952, pages 774-779.

1. AN IMPROVED SYNTHETIC FIBROUS MATERIAL COMPRISING A LINEAR HIGHMOLECULAR WEIGHT SYNTHETIC FIBROUS POLYMER SELECTED FROM THE GROUPCONSISTING OF POLYCAPROLACTAM, POLYHEXAMETHYLENE ADIPAMIDE ANDPOLYETHYLENE - TEREPHTHALATE TO WHICH THERE HAS BEEN ADDED ANANTI-STATIC COMPOUND HAVING THE GENERAL FORMULA